Protein in the Vegan Diet

Summary:
It is easy for a vegan diet to meet recommendations for protein, as
long as calorie intake is adequate. Strict protein combining is not
necessary; it is more important to eat a varied diet throughout the
day.

Some
Americans are obsessed with protein. Vegans are bombarded with
questions about where they get their protein. Athletes used to eat
thick steaks before competition because they thought it would improve
their performance. Protein supplements are sold at health food
stores. This concern about protein is misplaced. Although protein is
certainly an essential nutrient which plays many key roles in the way
our bodies function, we do not need huge quantities of it. Only about
one calorie out of every 10 we take in needs to come from protein.
Vegan athletes, especially in the early stages of training, may have
higher protein needs than vegans who exercise moderately or who are
not active. Vegan athletes’ protein needs can range from 0.36 to
0.86 grams of protein per pound 2. Protein supplements are not
needed to achieve even the highest level of protein intake.

How much
protein do we need? The RDA recommends that we take in 0.8 grams of
protein for every kilogram that we weigh (or about 0.36 grams of
protein per pound that we weigh) 1. This recommendation includes a
generous safety factor for most people. When we make a few
adjustments to account for some plant proteins being digested
somewhat differently from animal proteins and for the amino acid mix
in some plant proteins, we arrive at a level of 0.9 gram of protein
per kilogram body weight (0.41 grams per pound). If we do a few
calculations we see that the protein recommendation for vegans
amounts to close to 10% of calories coming from protein. [For
example, a vegan male weighing 174 pounds could have a calorie
requirement of 2,600 calories. His protein needs are calculated as
174 pounds x 0.41 g/pound = 71 grams of protein. 71 grams of protein
x 4 calories/gram of protein = 284 calories from protein. 284 divided
by 2,600 calories = 10.9% of calories from protein.] If we look at
what vegans are eating, we find that, typically, between 10-12% of
calories come from protein 3. This contrasts with the protein
intake of non-vegetarians, which is close to 14-18% of calories.

So, in the
United States it appears that vegan diets are commonly lower in
protein than standard American diets. Remember, though, with protein,
more (than the RDA) is not necessarily better. There do not appear to
be health advantages to consuming a high protein diet. Diets that are
high in protein may even increase the risk of osteoporosis 4 and
kidney disease 5.

Additional food should be added to these menus to provide adequate calories and to meet requirements for nutrients besides protein.

Table 2 shows the amount of protein in various vegan foods and also
the number of grams of protein per 100 calories. To meet protein
recommendations, the typical moderately active adult male vegan needs
only 2.2 to 2.6 grams of protein per 100 calories and the typical
moderately active adult female vegan needs only 2.3 to 2.8 grams of
protein per 100 calories. These recommendations can be easily met
from vegan sources.

Table 2: Protein Content of Selected Vegan Foods

FOOD

AMOUNT

PROTEIN

PROTEIN

(gm)

(gm/100 cal)

Tempeh

1 cup

31

9.6

Soybeans, cooked

1 cup

29

9.6

Seitan

3 ounces

21

17.5

Lentils, cooked

1 cup

18

7.8

Black beans, cooked

1 cup

15

6.7

Kidney beans, cooked

1 cup

15

6.8

Chickpeas, cooked

1 cup

15

5.4

Pinto beans, cooked

1 cup

15

6.3

Lima beans, cooked

1 cup

15

6.8

Black-eyed peas,
cooked

1 cup

13

6.7

Veggie burger

1 patty

13

18.6

Veggie baked beans

1 cup

12

5.0

Tofu, firm

4 ounces

11

10.6

Tofu, regular

4 ounces

10

10.7

Bagel

1 med. (3.5 oz)

10

3.9

Quinoa, cooked

1 cup

8

3.7

Peas, cooked

1 cup

8

6.6

Textured Vegetable
Protein (TVP),
cooked

1/2 cup

8

15.0

Peanut butter

2 Tbsp

8

4.1

Veggie dog

1 link

8

13.3

Spaghetti, cooked

1 cup

8

3.7

Almonds

1/4 cup

8

3.7

Soy milk, commercial,
plain

1 cup

7

7.0

Whole wheat bread

2 slices

7

5.2

Almond butter

2 Tbsp

7

3.4

Soy yogurt, plain

8 ounces

6

4.0

Bulgur, cooked

1 cup

6

3.7

Sunflower seeds

1/4 cup

6

3.3

Cashews

1/4 cup

5

2.7

Spinach, cooked

1 cup

5

13.0

Broccoli, cooked

1 cup

4

6.7

Sources: USDA Nutrient Database for Standard Reference, Release 24,
2011 and manufacturers’ information.The recommendation for protein for adult male vegans is around 63
grams per day; for adult female vegans it is around 52 grams per day.

It is very
easy for a vegan diet to meet the recommendations for protein.
Nearly all vegetables, beans, grains, nuts, and seeds contain some,
and often much, protein. Fruits, sugars, fats, and alcohol do not
provide much protein, so a diet based only on these foods would have
a good chance of being too low in protein. However, not many vegans
we know live on only bananas, hard candy, margarine, and beer. Vegans
eating varied diets containing vegetables, beans, grains, nuts, and
seeds rarely have any difficulty getting enough protein as long as
their diet contains enough energy (calories) to maintain weight. [See
Feeding Vegan Kids, Pregnancy and the Vegan Diet, and the section on lactation (page 186, in Simply Vegan), for details about protein needs during these special times.]

What about
combining or complementing protein? Doesn’t that make the protein
issue much more complex? Let’s look at a little background on the
myth of complementing proteins. Protein is made up of amino acids,
often described as its building blocks. We actually have a biological
requirement for amino acids, not for protein. Humans cannot make nine
of the twenty common amino acids, so these amino acids are considered
to be essential. In other words, we must get these amino acids from
our diets. We need all nine of these amino acids for our body to make
protein.

Some
people say that eggs, cow’s milk, meat, and fish are high quality
protein. This means that they have large amounts of all the essential
amino acids. Soybeans, quinoa (a grain), and spinach also are
considered high quality protein. Other protein sources of non-animal
origin usually have all of the essential amino acids, but the amounts
of one or two of these amino acids may be low. For example, grains
are lower in lysine (an essential amino acid) and legumes are lower
in methionine (another essential amino acid) than those protein
sources designated as high quality protein.

Frances
Moore Lappe, in her book Diet for a Small Planet 6 advocated the
combining of a food low in one amino acid with another food
containing large amounts of that amino acid. This got to be a very
complicated process, with each meal having specific amounts of
certain foods in order to be certain of getting a favorable amino
acid mix. Many people got discouraged with the complexity of this
approach. Actually, Lappe was being overly conservative to avoid
criticism from the “Nutrition Establishment.” She has since
repudiated strict protein combining, saying, “In combating the myth
that meat is the only way to get high quality protein, I reinforced
another myth. I gave the impression that in order to get enough
protein without meat, considerable care was needed in choosing foods.
Actually it is much easier than I thought” 7.

12-3/4 cups of cooked corn OR 8 large potatoes OR 2-1/2 cups of tofu OR 15-1/2 cups of cooked brown rice

Any one of
the above foods, eaten in the amount specified, would provide the
recommended amounts of all essential amino acids for an adult male.
Women would need about 20% less of each food due to lower
recommendations. This concept is illustrated below:

We
recommend eating a variety of unrefined grains, legumes, seeds, nuts,
and vegetables throughout the day, so that if one food is low in a
particular essential amino acid, another food will make up this
deficit 8,9.

As an
extreme example, even if you only ate one kind of grain, bean,
potato, or vegetable as a protein source, and ate enough of that
food, you could meet your protein and amino acid needs. Admittedly,
it would be a very monotonous way to eat and you might miss out on
other nutrients. We point this out, however, to illustrate the idea
that almost all non-animal protein sources contain all of the
essential amino acids. Table 3 above shows the amount of rice,
corn, potatoes, or tofu that an adult male would need to eat if he
relied on only one food as a protein source. Women would need about
20% less food because of women’s lower protein requirements.

Rodriguez NR, DiMarco NM, Langley S. Position of the American
Dietetic Association, Dietitians of Canada, and the American College
of Sports Medicine: Nutrition and athletic performance. J Am Diet
Assoc 2009;109:509-27.

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